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Transcription does what?
Makes it usable � into mRNA and the body can read this
Makes into functional proteins
hereditary factors responsible for traits
different forms of genes
Rules of Inheritance
- Alleles of the same gene separate during gamete formation
- Alleles of different genes are inherited independently
What is a Gene?
- Genes are made of nucleic acids
- Nucleic acids are made of building blocks called nucleotides
Nucleotides have three components, what are they?
- Sugar molecule (ribose or deoxyribose)
- Phosphate molecule
- Nitrogen-containing molecule (adenine, guanine, cytosine, thymine, uracil)
Nucleotides are linked in a chain through
DNA molecules are made of two chains of
nucleotides wound around each other in a helix
Base pairs hold the chains together
- A pairs with T
- G pairs with C
The Human Genome Project:
Sequencing DNA and Cataloguing Genes
the collection of DNA molecules that is characteristic of an organism
Genomics is the
- analysis of DNA sequences that make up a genome
- Genomics involves DNA sequencing technology, robotics, and computer science
The Human Genome Project determined the sequence of nucleotides in the DNA of the human genome
A Milestone in Genetics:
- fX174, the First DNA Genome Sequenced
- fX174 is a virus that has single-stranded DNA as its genetic material.
- Frederick Sanger sequenced the genome of fX174 in 1977
- Gregor Mendel postulated the existence of particular factors�now called genes�to explain how traits are inherited.
Alleles, the alternate forms of genes, account for
heritable differences among individuals.
James Watson and Francis Crick elucidated the structure of DNA, a macromolecule composed of two complementary chains of nucleotides.
DNA is the hereditary material of all life forms except some types of viruses, in which what is the hereditary material?
RNA is the hereditary material.
The Human Genome Project determined the
sequence of nucleotides in the DNA of the human genome.
Sequencing the DNA of a genome provides the data to identify and catalogue all the genes of an organism.
DNA as the Genetic Material
Information flows from
DNA to RNA to protein.
In all cellular organisms, the genetic material is
The genetic material
- Must be able to replicate
- Must contain information
- Must be able to change
- DNA Replication is based on the complementary nature of the
- two strands of duplex DNA molecules.
When the two parental strands are separated, the separated strands can serve as
template for the synthesis of new strands.
New strands are assembled by incorporating nucleotides according to
At the end of replication, each template strand is paired with a newly synthesized
DNA replication is catalyzed by
- During transcription, an RNA molecule is synthesized from a DNA template.This messenger RNA (mRNA) molecules contains the information needed to synthesize a polypeptide.
- During translation, the triplet codons in the RNA specify the incorporation of particular what?
- amino acids into a polypeptide chain.
the collection of all the different proteins in an organism.
Humans have between ____ and ___ genes in the genome and hundreds of thousands of proteins in the proteome.
20,000 and 25,000
the study of all the proteins in cells.
The Central Dogma of Molecular Biology
The flow of information is DNA � RNA� protein.
Some viruses can use RNA as a template for the synthesis of DNA in
Many genes do not encode polypeptides; their end-products are
Changing Genetic Information
When DNA replicates, each strand of a duplex molecule serves as the template for the synthesis of a
When genetic information is expressed, one strand of a gene�s DNA duplex is used as a template for the synthesis of a
complementary strand of DNA.
For most genes, RNA synthesis (transcription) generates a molecule (the RNA transcript) that becomes
a messenger RNA (mRNA).
Coded information in an mRNA is translated into a sequence of amino acids in a
The genetic variability created by mutation is the basis for
Variation in the DNA sequence makes it possible for species to
evolve over time.
Organisms with similar DNA sequences are descended from a
A phylogenetic tree, or phylogeny, represents the
historical relationships among organisms.
Evolution depends on the occurrence, transmission, and spread of
mutant genes in groups of organisms.
DNA sequence data provide a way of studying the
historical process of evolution.
Geneticists approach their science from different points of view�
from that of a gene, a DNA molecule, or a population of organisms.
- Based on analysis of the outcomes of crosses between different strains of organisms.
- Can be coordinated with studies of the structure and behavior of chromosomes.
- Encompasses transmission genetics and studies of the nature of the genetic material
- Studies the replication, expression, and mutation of genes at the molecular level.
- Rooted in the study of DNA sequences and the manipulation of DNA molecules.
- Individuals within a population may carry different alleles of genes.
- Population genetics is based on analyzing allele frequencies in a population and determining whether these frequencies changes over time.
- Population genetics includes evolution and the inheritance of complex traits.
In classical genetic analysis, genes are studied by following the
inheritance of traits in crosses between different strains of an organism.
In molecular genetic analysis, genes are studied by
isolating, sequencing, and manipulating DNA and by examining the products of gene expression.
In population genetic analysis, genes are studied by
assessing the variability among individuals in a group of organisms.
Genetics in Agriculture:
- Selective Breeding
- Genetically Modified Organisms
Genetically Modified Organisms (GMOs) are have been altered by
the introduction of foreign genes.
Genetics in Medicine
- Inborn Errors of Metabolism are metabolic abnormalities caused to mutant alleles.
- Genetic Counselors advise people about inheritance of genetic diseases.
- new ways to detect mutant alleles.
- new ways to treat diseases.
biotechnology industry, pharmaceutical industry.
paternity testing, forensics, identification
Discoveries in genetics are changing procedures and practices in agriculture and medicine.
Advances in genetics are raising ethical, legal, political, social, and philosophical questions.